The subject matter herein relates generally to light assemblies.
Some current lighting applications utilize a light pipe with a light source to distribute the light generated by the light source over a distance. Such lighting applications may include, for example, automotive exterior lighting, automotive interior ambient lighting, commercial lighting, lighting in household devices, and the like. The light pipe is typically a cylindrical, transparent structure. The light pipe may be aligned with the light source such that the light source is located at an end of the light pipe. The light generated by the light source is received at the end of the light pipe and transmitted longitudinally along the length of the light pipe by internal reflection. The light may be emitted from the surface of the light pipe along the length of the light pipe in a direction transverse to the longitudinal direction of the light pipe. In addition, or alternatively, the light may be emitted in an axial direction through a distal end of the light pipe opposite to the end proximate to the light source that receives the light. To increase light intensity and/or improve light gradient along the light pipe, a different light source may be located at either end of the light pipe.
Light assemblies that include light pipes advantageously allow for the transmission of light over a designated distance (e.g., defined by the length of the light pipe) using only a single light source at an end of the light pipe instead of multiple light sources spaced along a length. As such, the light source and associated components that generate the light may be hidden or disguised in the application so as to not distract from the light display.
Light assemblies that are used in external applications, such as for automotive exterior lighting, are exposed to contaminants and harsh environmental conditions. For example, an external lighting assembly may experience moisture, dirt, dust, sand, chemicals, extreme temperatures, vibrations and other forces, and the like, on a daily basis, especially for vehicle applications located at the front of the vehicle or near the wheels. Generally, light pipe lighting assemblies include a housing that holds the light source and shields the light source and associated components (e.g., printed circuit board, wires, and other electrical components). However, the housing does not fully surround and protect the light source because the housing generally includes one or more openings used to allow wires to extend from the housing, to couple to the light pipe, and/or to provide an unobstructed optical path from the light source to the light pipe. Therefore, contaminants may enter the housing through the openings, where the contaminants may damage the generation and transmission of light, or may even damage the light generating components and circuitry, which would require a repair. Additionally, the light pipe itself may not have sufficient abrasion resistance properties to withstand damage from sand, gravel, and the like, without a diminution of optical properties
To prohibit damage from contaminants and harsh environmental conditions, some known light assemblies attempt to seal one or more openings of the housing using various adhesives that are applied during assembly. For example, glue, epoxy, potting compounds, or the like may be applied to the end of a light pipe and/or to the opening of the housing to couple and seal the two parts. These compounds may be messy, labor intensive to apply, and/or expensive. In addition, once the adhesive sets at the assembly plant, the orientation of the light pipe is fixed relative to the housing, which limits the flexibility of integrating the light assembly within applications, such as vehicle running boards. Alternatively, or in addition, some known light assemblies use gaskets, such as peripheral seals, to provide a seal between the light pipe and the housing. But, using gaskets may be expensive, labor intensive, and risk failure in the elements (e.g., in cold temperatures). Such gaskets may also increase the overall size of the light assembly. A need remains for a sealed light assembly that may be used in external applications that avoids at least some of the identified issues and allows for some dimensional flexibility and shape tolerance between the light pipe and the housing.